And,
It is a divinely revealed truth that sins bring punishments inflicted by God's sanctity and justice. These must be expiated [atoned, be compensated] either on this earth through the sorrows, miseries and calamities of this life and above all through death, or else in the life beyond through fire and torments or 'purifying' punishments.” (INDULGENTIARUM DOCTRINA; cp. 1. 1967)
However, this myth is based upon a false premise of justification
For in contrast to Scripture, in which God justifies the unGodly by counting his faith as righteousness, while purifying his heart by faith by which he is regenerated, (Rm. 4:5; Acts 15:7-9) yet it must be the kind of a faith which effects obedience, under Roman soteriology God justifies the Godly based upon his holiness, as one is "formally justified and made holy by his own personal justice and holiness.” (Catholic Encyclopedia>Sanctifying Grace) Which is normally initially "infused" via regeneration effected by the act itself of sprinkling of water (ex opere operato), thus at that point the newly baptized is fit to enter Heaven. Thus Abraham must have become born again in Gn. 15:6.
However, due to failure to maintain this and as justification is based one one's own holiness, then under the Roman system of salvation, the RC (the EOs reject the purgatory of Rome) typically must endure postmortem "purifying torments" for an indeterminate time in purgatory until they atone for sins and once again become good enough to enter Heaven.
In seeking to support this tradition with Scripture, RC invoke 2 Maccabees 12:43ff, but which only teaches praying and making offerings for the dead if perhaps God may forgive them, and which was for those died due to mortal sin, which Rome holds their is no hope for.
Other texts either refer to present chastisement or the lost, or 1Cor. 3:8ff, which only refers to suffering the loss of rewards (and implicitly the Lord's displeasure), and which only occurs after the Lord's return, not commencing at death.
AMEN
Since Purgatory pertains to sanctification -- not justification -- I'll grant there's a false premise being interjected into the discussion.
For in contrast to Scripture, in which God justifies the unGodly by counting his faith as righteousness, while purifying his heart by faith by which he is regenerated,
But in the Catholic view, sanctification isn't imputed (nor is justification, but see prior comment). "Nothing unclean shall enter." (Rev. 21:27). In our view, "snow covered dungheaps" don't enter heaven. Only souls which are inherently righteous and clean enter. If the necessary cleansing isn't effected while the soul remains attached to the body, then God is merciful and provides that "final sanctification" (Purgatory) so that the justified soul can enter.
Other texts either refer to present chastisement . . .
Indeed. For example:
4 In your struggle against sin you have not yet resisted to the point of shedding your blood. 5 And have you forgotten the exhortation which addresses you as sons?—
“My son, do not regard lightly the discipline of the Lord, nor lose courage when you are punished by him. 6 For the Lord disciplines him whom he loves, and chastises every son whom he receives.”
7 It is for discipline that you have to endure. God is treating you as sons; for what son is there whom his father does not discipline? 8 If you are left without discipline, in which all have participated, then you are illegitimate children and not sons. 9 Besides this, we have had earthly fathers to discipline us and we respected them. Shall we not much more be subject to the Father of spirits and live? 10 For they disciplined us for a short time at their pleasure, but he disciplines us for our good, that we may share his holiness. 11 For the moment all discipline seems painful rather than pleasant; later it yields the peaceful fruit of righteousness to those who have been trained by it." Heb. 12:4-11.
While this certainly encompasses earthly discipline, I see nothing in the text (or others like it) that indicate such is necessarily limited to our earthly sojourn.
and as justification is based one one's own holiness,
No, no, no, NO, NO!!! Strawman alert!! Justification is wrought by God's grace; we are justified by what God by his grace does through us. (But see first comment; Purgatory and justification are 2 distinct things).
In seeking to support this tradition with Scripture, RC invoke 2 Maccabees 12:43ff, but which only teaches praying and making offerings for the dead
I'll grant those verses are consonant with the idea of Purgatory, though not alone proving it. But, that said, the idea of an after-life purification is Jewish in origin. For example:
Gan Eden and Gehinnom
The place of spiritual reward for the righteous is often referred to in Hebrew as Gan Eden (GAHN ehy-DEHN) (the Garden of Eden). This is not the same place where Adam and Eve were; it is a place of spiritual perfection. Specific descriptions of it vary widely from one source to another. One source says that the peace that one feels when one experiences Shabbat properly is merely one-sixtieth of the pleasure of the afterlife. Other sources compare the bliss of the afterlife to the joy of sex or the warmth of a sunny day. Ultimately, though, the living can no more understand the nature of this place than the blind can understand color.
Only the very righteous go directly to Gan Eden. The average person descends to a place of punishment and/or purification, generally referred to as Gehinnom (guh-hee-NOHM) (in Yiddish, Gehenna), but sometimes as She'ol or by other names. According to one mystical view, every sin we commit creates an angel of destruction (a demon), and after we die we are punished by the very demons that we created. Some views see Gehinnom as one of severe punishment, a bit like the Christian Hell of fire and brimstone. Other sources merely see it as a time when we can see the actions of our lives objectively, see the harm that we have done and the opportunities we missed, and experience remorse for our actions. The period of time in Gehinnom does not exceed 12 months, and then ascends to take his place on Olam Ha-Ba.
Only the utterly wicked do not ascend at the end of this period; their souls are punished for the entire 12 months. Sources differ on what happens at the end of those 12 months: some say that the wicked soul is utterly destroyed and ceases to exist while others say that the soul continues to exist in a state of consciousness of remorse. Judaism 101
And we find this same idea carried forward into the immediate post-Apostolic age:
"[T]hat allegory of the Lord which is extremely clear and simple in its meaning, and ought to be from the first understood in its plain and natural sense...Then, again, should you be disposed to apply the term 'adversary' to the devil, you are advised by the (Lord's) injunction, while you are in the way with him,'to make even with him such a compact as may be deemed compatible with the requirements of your true faith. Now the compact you have made respecting him is to renounce him, and his pomp, and his angels. Such is your agreement in this matter. Now the friendly understanding you will have to carry out must arise from your observance of the compact: you must never think of getting back any of the things which you have abjured, and have restored to him, lest he should summon you as a fraudulent man, and a transgressor of your agreement, before God the Judge (for in this light do we read of him, in another passage, as 'the accuser of the brethren,' or saints, where reference is made to the actual practice of legal prosecution); and lest this Judge deliver you over to the angel who is to execute the sentence, and he commit you to the prison of hell, out of which there will be no dismissal until the smallest even of your delinquencies be paid off in the period before the resurrection. What can be a more fitting sense than this? What a truer interpretation?" Tertullian, A Treatise on the Soul, 35(A.D. 210)
"It is one thing to stand for pardon, another thing to attain to glory: it is one thing, when cast into prison, not to go out thence until one has paid the uttermost farthing; another thing at once to receive the wages of faith and courage. It is one thing, tortured by long suffering for sins, to be cleansed and long purged by fire; another to have purged all sins by suffering. It is one thing, in fine, to be in suspense till the sentence of God at the day of judgment; another to be at once crowned by the Lord." Cyprian of Carthage, To Antonianus, Epistle 51(55):20(A.D. 253)
And between the Jewish outlook and the view expressed in the Early Church we find the Apostles -- who were Jews. The similarity in viewpoint to me is not difficult to explain.
the EOs reject the purgatory of Rome
There are some differences of viewpoint, but the E.O. are in agreement with the essential notion of a temporary punishment for sin which is imposed in the afterlife. From The Orthodox Response to the Latin Doctrine of Purgatory
When giving in this answer (June 14th), Bessarion explained the difference of the Greek and Latin doctrine on this subject. The Latins, he said, allow that now, and until the day of the last judgment, departed souls are purified by fire, and are thus liberated from their sins; so that, he who has sinned the most will be a longer time undergoing purification, whereas he whose sins are less will be absolved the sooner, with the aid of the Church; but in the future life they allow the eternal, and not the purgatorial fire. Thus the Latins receive both the temporal and the eternal fire, and call the first the purgatorial fire. On the other hand, the Greeks teach of one eternal fire alone, understanding that the temporal punishment of sinful souls consists in that they for a time depart into a place of darkness and sorrow, are punished by being deprived of the Divine light, and are purified—that is, liberated from this place of darkness and woe—by means of prayers, the Holy Eucharist, and deeds of charity, and not by fire. The Greeks also believe, that until the union of the souls to the bodies, as the souls of sinners do not suffer full punishment, so also those of the saints do not enjoy entire bliss. But the Latins, agreeing with the Greeks in the first point, do not allow the last one, affirming that the souls of saints have already received their full heavenly reward.
* * *
To all this the Orthodox party gave a clear and satisfactory answer. [5] They remarked, that the words quoted from the book of Maccabees, and our Saviour's words, can only prove that some sins will be forgiven after death; but whether by means of punishment by fire, or by other means, nothing was known for certain. Besides, what has forgiveness of sins to do with punishment by fire and tortures? Only one of these two things can happen: either punishment or forgiveness, and not both at once.
So the E.O. agree that there can be after-life forgiveness of sin, and that such is cleansed "by means of prayers, the Holy Eucharist, and deeds of charity," and they agree with Catholics that such state is temporary. The E.O. objection is largely centered on the Latin notion of a temporary "purging fire." The Orthoodox relegate "fire" solely to the eternal fire of punishment.